/**
 * Description:
 * Author: taimi 37310
 * Version: 1.0
 * Create Date Time: 2022/4/11 21:40.
 * Update Date Time:
 *
 * @see
 */
public class Main {
    public static void main(String[] args) {
        String oldname = "aaa.jsp";
        String ext = oldname.substring(oldname.lastIndexOf("."));
        System.out.println(ext);
    }
}
